Lung adenocarcinoma of a scar left by a past asymptomatic histoplasmosis infection in a nonsmoker 79yr female

Hi, From the scientific perspective, your question basically involves two major issues: One, what is the temporal association (time-line) between occurrence of histoplasmosis and appearance of calcification on lung imaging by CT scan? Two, is there an association between scarring caused by histoplasmosis and subsequent development of lung cancer in that scar tissue? Ohio, Nebraska, and Louisiana form a triangular region with a high prevalence of histoplasmosis. This infection is caused by infection with the fungus Histoplasma capsulatum, which thrives on soil contaminated with droppings of birds and bats. Wind can carry spores from the soil, and thus spread the infection. The spores are inhaled and lodge in the lungs. Within 1 to 2 weeks after the initial infection, the body’s immune system begins to wall off the infected part of the lung by forming a capsule around it which eventually calcifies. The time required for calcification varies in different patients, and ranges from a few months to a few years. Generally, calcification occurs faster in younger patients. In an excellent review on histoplasmosis, Gurney and Conces narrate the story of 3 members of a family infected with this fungus. The youngest son, aged 5 years, developed calcifications after 9 months, the 21-year-old son after 15 months, and their father after 24 months. (http://radiology.rsnajnls.org/cgi/reprint/199/2/297). These same authors also describe the delayed manifestations of histoplasmosis, which are of three types: histoplasmoma, broncholithiasis, and mediastinal granuloma and mediastinal fibrosis. They do not, as you notice, describe adenocarcinoma as a consequence of histoplasmosis. However, Kokichi Yoneda from the University of Kentucky College of Medicine reported that “seventeen cases of pulmonary scar carcinomas were found in 112 surgically resected pulmonary carcinomas from 1985 through 1988 in a hospital situated in a histoplasmosis endemic area.” (http://www3.interscience.wiley.com/cgi-bin/abstract/112686872/ABSTRACT?CRETRY=1&SRETRY=0)

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